Carton unstacking machine



Jan. 22, 1963 c. R. BOLLER 7 3,074,595

I CARTON UNSTACKING MACHINE Original Filed Sept. 26, 1957 8 Sheets-Sheet1.

f INVENTOR.

6201198 )2 ,Bo/Zer Jan. 22, 1963 c. R. BOLLER CARTON UNSTACKING MACHINEOriginal Filed Sept. 26, 1957 8 Sheets-Sheet 2 INVENT OR.

Jan. 1963 c. R. BOLLER 3,074,595

CARTON UNSTACKING MACHINE Original Filed Sept. 26, 1957 8 Sheets-Sheet 3INV ENT OR.

Jan. 22, 1963 c. R. BOLLER 3,074,595

CARTON UNSTACKING MACHINE Original Filed Sept. 26, 1957 8 Sheets-Sheet 4INVENTOR.

Ci ar/291? ,Baller Jan. 22, 1963 c. R. BOLLER 3,

v I CARTON UNSTACKING MACHINE Original Filed Sept. 26, 1957 8Sheets-Sheet 5 INVENTOR Ufiar/es I? ,Baller Jan. 22, 1963 c. R. BOLLER3,074,595

CARTON UNSTACKING MACHINE Original Filed Sept. 26, 1957 8 Sheets-Sheet 6Jan. 22, 1963 c. R. BOLLER 3,074,595

CARTON UNSTACKING MACHINE Original Filed Sept. 26, 1957 8 Sheets-Sheet'7 INVENT OR.

United States Patent 3,074,595 CARTON UNSTACKING MACHINE Charles R.Boiler, St. Paul, Minn, assignor to Standard Conveyor Company, St. Paul,Minn., a corporation of Minnesota Original application Sept. 26, 1957,Ser. No. 686,431. 20, 1959, Ser. No.

Divided and this application Feb. 795,312

9 Claims. (Cl. 221--221) This invention relates to improvements inmachines for automatically unstacking cartons, e.g., packages, cases orother units that are received in the form of a succession of stacks andfor delivering the individual cartons to a conveyor or otherwisedisposing of them, as individual units. For convenience of reference allof such units are herein referred to as cartons.

Many types of goods, for example, packaged foods and bottled beveragesare stored in cartons and the latter are stacked in tiers. Each stack isoften supported on a pallet, skid or other portable platform in awarehouse. Such stacks of cartons must be disassembled or unstacked whenthe stored goods are to be sold, distributed, used or otherwise disposedof.

It is an obiect of this invention to provide an unusually simple,compact and reliable machine adapted to automatically unstack cartonsreceived in stacks and delivered to the unstacking mechanism either onpallets or by a lift truck provided with clamp attachment withoutpallets.

Another object is to provide a machine of the class described adapted toreceive stacks wherein the individual cartons are disposed in variouspositions in an interlocking pattern of tiers and provided with novelmeans for discharging the individual cartons from the machine in lineand all in the same relative position.

A further object is to provide in an unstacking machine novelinterlocking electrical controls affording continuous, reliable andautomatic operation.

Referring to the accompanying drawings which illustrate one embodimentof my invention, by way of example and not for the purpose oflimitation:

FIGURE 1 is a schematic front elevational view showing the principalmechanical elements of the machine and a stack of cartons in theirpositions at the start of a cycle of operation;

FIG. 2 is a plan view of the principal mechanical elements of themachine .in the same starting position;

FIG. 3 is a front elevational view similar to FIG. 1 but showing themachine elements and cartons in the positions they occupy at anotherstage of the operation;

FIG. 4 is a plan view similar to FIG. 2 but showing the mechanism andcartons in the position shown in FIG 3;

FIG. 5 is a front elevational view like FIGS. 1 and 3 but showing themechanism and cartons in a succeeding position in the cycle ofoperation;

FIG. 6 is a plan view showing the mechanism and cartons in the positionscorresponding to those shown in FIG. 5;

FIG. 7 is a somewhat diagrammatic perspective view showing the principalconveyor members, pusher mechanism and associated limit switches;

PEG. 8 is a diagrammatic perspective view showing the principal limitswitch controls associated with the hoist and clamping jaw mechanism,and also showing the hydraulic actuated mechanism for the hoist carriageand carton clamping jaws;

FIG. 9 is a perspective view showing the empty pallet stacking mechanismand associated limit switches with portions broken away to show partsotherwise concealed;

FIG. 10 is a wiring diagram showing the empty pallet stacking controlcircuit;

FIG. 11 is a front elevational view showing the layer receiving platformand discharge conveyor more in detail;

FIG. 12 is a wiring diagram showing the hoist and clamp controlcircuits, and

FIG. 13 is a wiring diagram showing the conveyor and pusher controlcircuits.

Mechanical Construction Stacks of cartons to be unstacked are fed to themachine on a feed conveyor 20. As indicated in FIG. 7, this conveyor ispreferably of the live roller type having a series of parallel loadsupporting rollers 21 operatively connected to an electric motor 22adapted to be energized periodically to feed stacks of cartons or otherunits referred to as cartons into the machine. Each stack may comprise amultiplicity of cartons 23 arranged in tiers or layers and each layer isordinarily composed of a plurality of rows. Such stacks may be supportedon a pallet 24 or, in the alternative, may be supported directly on theconveyor 20 if pallets are not required. This conveyor delivers thestacks, one at a time, to a first platform 25 defining an unstackingarea. As indicated in FiG. 7, the platform 25 is preferably providedwith load supporting rollers 26 extending in parallel relation to therollers 21 of the conveyor 20.

Associated with the platform 25 and projecting above it at its endopposite the conveyor 20 is a hoist indicated generally by the numeral27. As best shown in FIG. 8, a vertically movable carriage 28 isoperatively connected to hydraulic means including a cylinder 29 whichis supported on the hoist frame. A pair of clamping jaws 30, 39a aremounted on the carriage 28 and have vertically disposed grippingsurfaces extending in parallel relation one to the other for frictionalengagement with opposite sides of one or more layers. The hoist andclamping jaws are adapted to lift a plurality of layers at a time abovethe platform 25, as indicated in FIGS. 3 and 5. The jaw 3th: is mountedon a pair of horizontally extending arms 300 which are attached to andcarried by the carriage 28. Another pair of horizontally extending arms31 movahly support the jaw 30 and are slidable horizontally in guideways31a carried by the carriage 23. Limited oscillating movement of the jaws30 and 30a about a vertical axis is provided by means of pivot pins 30bwhich connect the central portion of each jaw to its supporting arms.The hoist has a rigid base 32, a pair of vertically extending channelshaped guide members 33 and a rigid cap plate 34. The upper end ofhydraulic cylinder 29 is anchored on the plate 34 and a piston withinthe hoist cylinder 29 is operatively connected to the carriage 28 by arod 35. Antifriction rollers 33a (FIG 4) are mounted on the carriage 28to run in the channels of the guide members 33.

Extending at one side of the platform 25 and at a common elevationtherewith is a second platform 36 defining a layer receiving area. Asindicated in FIGS. 7 and 11, platform 36 is preferably provided withload supporting rollers 37 which are operatively connected to anelectric motor 38 adapted to be energized to convey layers of articlesreceived from the platform 25 to a row discharge conveyor indicatedgenerally at 39. This convey-or is also of the live roller type havingrollers 39a for supporting the cartons operatively connected to anelectric motor 40. The load supporting rollers 39a of conveyor 39 areinclined so that the cartons received on this conveyor are tilted awayfrom the platform 36 to contact guiding means indicated generally at 41extending along the lower side of the discharge conveyor.

Pusher Mechanism FIGS. 1-4 and 7 show mechanism suitable fortransferring layers of cartons from the unstacking platform 25 to thelayer receiving platform 36. This same mechanism is operative totransfer empty pallets from the platform 25 to a pallet stackingelevator 55 and includes a pusher bar 56 which is movable across theplatform 25 from a starting position indicated in FIGS. 1 and 2 to anend position indicated in FIGS. 3 and 4 and back to the startingposition. A pair of arms 57 are rigidly connected to the bar 56 andproject between rollers of the platform 25 from a supporting carriage 58movable along guide rails 59 positioned beneath the platform 25.

Hydraulic means are provided for actuating the carriage 58 with therequired reciprocating movement along the rails 59. An elongatedsubstantially horizontally extending cylinder 60 is suitably mounted onthe machine frame beneath the platform 36 and a piston within thecylinder is connected by a rod 61 to the carriage 58. Fluid underpressure is admitted to and exhausted from opposite ends of the cylinder60 under control of a valve 62 (FIG. 7) and solenoids 63 and 64 haveplungers which are operatively connected to a valve 62 to activate thepusher mechanism when either of these solenoids is energized, ashereinafter described. When solenoid 63 is energized the valve becomesoperative to admit fluid under pressure to the right end of the cylinder60 while exhausting fluid from the left end. To reverse the movement ofthe pusher bar the solenoid 64 is energized, thereby exhausting fluidfrom the right end and admitting pressure fluid to the left end of thecylinder.

Pallet Stacking Mechanism Pallet stacking elevator 55 has a deck definedby load supporting rollers 65 (FIG. 9) and is disposed at a slightincline so that the pallets will be carried by gravity on the rollers 65toward a stop 66 at the end of the elevator deck remote from theunstacking platform 25. Inclined rails 67 supporting the rollers 65 arein turn supported on a pair of cross frame members 68 and are guidedbetween vertically disposed fixed frame members 69. At their upper endsframe members 69 of each pair are connected together by horizontalmembers 70. Each horizontal member 70 supports a pair of spaced, pivoteddogs 71 which normally project above the elevator deck to support one ormore pallets in elevated position. The several dogs 71 are free to swingupward out of the path of each pallet as it is raised on the deckrollers 65. Upon the lowering of the deck the dogs return to theirhorizontally projecting position wherein they support the elevatedpallet or stack of pallets.

Pallet elevator 55 is movable from its lower position wherein itreceives individual pallets from platform 25 to an elevated position ator slightly above the elevation of the dogs 71. As shown, hydraulicmeans including a vertical cylinder 72 having a piston connected to thepallet elevator is provided to raise and lower the latter. Flow of fluidunder pressure to and from the upper and lower ends respectively of thecylinder 72 is under control of a valve indicated generally at 73.Solenoids 74 and 75 are provided for actuating this valve.

Hoist and Clamping Jaw Actaating Mechanism Fluid under suitable pressuremay be admitted to either end of the cylinder 29 and exhausted from theopposite end under control of a valve 76. This valve is spring biasedtoward a central position wherein the fluid pressure is locked inopposite ends of the cylinder 29. Solenoids 77 and 78 have plungersoperatively connected to the valve 76 to actuate it and cause the hoistto move up or down to predetermined positions. When the solenoid 78 isenergized, the valve is moved to such position as to cause fluid toenter the lower end of the cylinder 29 While allowing flow out of theupper end to thereby raise the hoist. When the solenoid 77 is energizedthe valve 76 is actuated to reverse the flow to and from the cylinderand thereby cause the hoist to move downward.

Clamping jaw 30 is also actuated by hydraulic means including ahorizontally extending cylinder 79 mounted on carriage 28 and having apiston and rod 80 operatively connected to the jaw 36. A valve 81controls the flow of pressure fluid to and from the cylinder 79. Thisvalve is also solenoid actuated, having a solenoid 82 adapted to beenergized to cause the jaw 30 to move inward to closed position and asolenoid 83 which is energized to cause the jaw to move outward to openposition. Flexible fluid conduits indicated at 84 and 85 connect thevalve 81 to opposite ends of the cylinder 29. interposed in the conduit85 is a pressure responsive switch actuating device disposed to actuatea normally open switch S11 to closed position when fluid pressure inconduit 85 reaches a value corresponding to the gripping pressurerequired to lift a stack of cartons in the grip of the jaws 30 and 30a.

Limit Switches Associated With Hoist and Clamping Jaws The location ofthese switches is approximately as indicated diagrammatically in FIG. 8.In addition to the pressure responsive switch S11 the control circuitincludes limit switches S2, S3, S5, S6, S7 and S8. Switch S2 has acontact 82a which is normally closed when the gripping jaw 30 is in itsopen position and a normally open contact S2b which is closed when thejaw 30 is in its closed position and in contact with cartons. Switch S2is mounted on the jaw 36 and has an actuating pin 20 projecting throughan opening in the jaw 30 as indicated in FIG. 8 for engagement withcartons at the inner side of the jaw. A normally open switch S3 isclosed when jaw 30 is in its open position. This switch may be mountedas indicated on a fixed support in the path of a finger projecting fromone of the arms 31 supporting the jaw 30.

Electric circuits for activating the hoist include the switches S5, S6,S7 and S8 all mounted on fixed supports along the path of the hoistcarriage 28 to be actuated thereby when the hoist reaches preselectedelevations. Switches S5 and S6 are normally open and are both closedwhen the hoist is in its top position. As the hoist starts down switchS5 opens and S6 remains closed until the hoist reaches an intermediateposition allowing switch S6 to open. Switch S7 at a lower elevation hasa normally closed contact 87a and a normally open contact 871). It isclosed at its normally open contact and opened at its normally closedcontact when the hoist reaches the elevation of this switch. Switch S8is normally open and is arranged to be closed when the hoist reaches thebottom limit of its movement.

Control Switches Associated With Conveyors and Pusher MechanismProjecting into the path of stacks of cartons on the feed conveyor 20 isa normally open switch S9 which is closed when a load or stack is placedon this conveyor.v Subsequently, upon delivery of the stack to theplatform 25, a switch S1 is actuated. This switch has a normally opencontact 81b and a normally closed contact Sla.

Switches S10, S12 and S13 are so located as to be actuated when thepusher bar 56 reaches predetermined positions in its cycle of operation.Switch S10 has a normally closed contact 810a and a normally open con--tact S10b. This switch is closed at its contact Sllttb and opened at810a when the pusher reaches a position near the end of its traveltoward the right side of the platform. Switch S12 is normally open andso located as to be closed when the pusher bar 56 is in its end positionat the left of the unstacking platform 25. Upon arrival of the pusherbar at its end position at the right hand side of the unstackingplatform switch S13 is closed.

An operating control for the rollers 37 of the layer receiving platform36 comprises a normallyclosed switch S14 mounted at one side of thisplatform and having an arm projecting into the path of the cartons. Whenthis arm is actuated by a carton approaching conveyor 39,,

switch S14 is opened. Further controls for motor 38 for operatingrollers 37 comprise a pair of normally closed switches S4 and 54a whichare actuated to open position as each row of cartons is received on thecarton delivery conveyor 39. Each of the switches S4 and S411 has an armwhich projects above and slightly beyond the anti-friction wheels 46 onthe guard rail 41. When either of these switches is open the operationof the motor 38 is interrupted.

Pallet Stacking Control Switches Three switches are provided to controlthe operation of the stacking mechanism. These are identified asswitches S15, S16 and S17 in FIGS. 9 and 10. Normally open switch S isclosed when a pallet is delivered against the stop 66 on the elevator55. Switch S16 is closed when the pallet elevator reaches the upperextremity of its movement to energize the down solenoid 74 and start thereturn of the elevator to its bottom position. Switch S17 is closed whenthe elevator is in its bottom or pallet receiving position. Switches S16and S17 are supported on suitable fixed supports attached to the framemembers of the pallet stacker and each has a spring arm projecting forengagement with a member of the elevator. Switch S15 is similarlymounted and has a member projecting in position to be actuated when apallet engages the stop 66. Solenoid valve 73 is of the type which holdsin either of its positions, i.e., for sending the deck 55 up or down,when actuated momentarily by either solenoid 74 or 75.

Electric Circuits PEG. 10 shows simple circuits for energizing thesolenoids 74 and 75 for actuating the valve 73 controlling the pallethoist operation and including the limit switches S15, S16 and S17. Thesecircuits will be readily understood without further detail explanation.

In FIG. 12 l have shown circuits which are primarily related to thehoist and clamp mechanism and whereby the solenoids actuating the valvesfor the hoist and clamps are energized. Relays R3, R4, R6 and R7 shownin FIG. 12 have coils which are included in circuits shown in FIG. 13.

FIG. 13 shows circuits including conveyor motors 22, 38 and 4t) and alsofor energizing solenoids 63 and 64 for operating the pusher controlvalve. The circuits shown in FIGS. 12 and 13 have interlockingconnections. Thus in FIG. 13 relays R8, R9 and R11 have coils includedin circuits shown in FIG. 12. As indicated in these wiring diagrams,each of the relays R1 to R14 inclusive has one or more pairs of armatureactuated spring contacts. All relay contacts and switches are shown intheir normal positions, i.e., in either open or closed circuit position,as when the several relays are deenergized. The several circuits will bebest understood from a description of the operation which follows:

In these wiring diagrams current supply conductors are indicated at 89and 9t representing the positive and negative sides of the circuitsrespectively.

Operation At the start of an operating cycle feed conveyor is notrunning, no load being positioned on this conveyor, layer pusher bar 56is back to the left closing switch S12, the hoist is in its top positionclosing switches S5 and S6 and clamp jaw 30 is in its open positionclosing switch S3. Switch S2 is open at contact S211 and closed at 32a.As will be evident from PKG. 13, conveyor rollers 37 connected to motor38 are operating since this motor is in series with normally closedswitches S4 and 84a and there are no cartons on the discharge conveyor39. The latter is normally in continuous operation as is the cartonturning belt 42. Also at the start of a cycle relay R3 is energizedthrough the circuit under control of closed switch S3, clamping jaw 31being in its open position. Relay R4 is energized through its circuitunder control of switch S12 which is held closed by the pusher bar whenin its left position. Relay R7 (FIG. 13) is also energized, switch S5being closed, relay R6 is energized through the circuit including closedswitch S6 and relay R11 is energized and is held in through its ownholding contacts and normally closed contact 810a.

Assuming that the stacks of cartons to be unstacked are supported onpallets, to start a cycle a load of cartons on a pallet is placed onfeed conveyor 20, as indicated in FIGS. 1 and 2, thereby closing switchS9. This switch now energizes relay R1 through the circuit fromconductor 89 including contacts C1 of relay R3, contacts C2 of relay R4,contacts C3 of relay R11, contact Sla of switch S1, switch S9 and thecoil of relay R1 to condue-tor as. Relay R1 is now held in through itsown contacts, and through a branch of this closed circuit, motor 22 ofthe feed conveyor is started. The load of cartons is then moved onconveyor 20 to platform 25 where switch S1 is actuated by the load. Thecircuit including contact 81a is thereby opened to deenergize relay R1and stop motor 22 operating conveyor rollers 21.

At the same time a circuit is closed at contact Slb including normallyclosed contacts C4 of relay R5 (FIG. l2), contacts C5 of relay R7,contacts C6 of relay R4, contacts C7 of relay R11, contact Slb of switchS1 and the coil of relay R2. This relay is thereby energized and willlock in through its own contacts C8 and normally closed contact 87a ofswitch 7 to cause solenoid 77 to be energized through a circuit whichincludes contacts C4 of relay R5, contacts C9 of relay R2 and the coilof solenoid 77. Downward movement of the hoist will continue untilswitch S7 is actuated to open a circuit at its normally closed contactSla. Relay R2 and solenoid 77 are thereby deenergized and downwardtravel of the hoist stops with the lower edges of the clamp jawsslightly above the pallet on platform 25.

Simultaneously a clamp activating circuit is closed at the normally opencontact 37b of switch 7. Since relay R11 is energized this circuitincludes contacts C10 of relay R11, contact S7 b, contacts C11 of relayR7, contacts C12 of relay R3 and the coil of solenoid 82. Valve 81 isthereby actuated to cause the clamp jaw 30 to move to closed position. Astack of cartons above platform 25 is, thereby clamped in the grip ofthe jaws 30, 30a. As the gripping pressure increases to thepredetermined maximum in the right end of cylinder 79 and in conduit 85,pressure responsive device 86 closes switch S11. Current is now fedthrough contacts C10 of R11, contact 87b, switch 11, 5% contact ofswitch S2 and the coil of relay 9.

Upward movement of the hoist follows due to the closing of a circuitthrough the coil of solenoid 78 actuating hoist valve 76. This circuitincludes contacts C13 of relay R2, contacts C14 of relay R9 and the coilof relay R8. Being thus energized, relay R8 is held in through its owncontacts C15 and solenoid 78 is energized to cause the hoist to move up.Included in this circuit are contacts C16 of relay R6 and contacts C17of relay R8.

The hoist then moves up to an elevation where it closes switch S6,thereby energizing relay R6 causing contacts C15 to open, and openingthe circuit supplying current to the coil of solenoid 78. Upwardmovement of the hoist is thereby stopped when it reaches a predeterminedelevation. i

As a further result of the closing of switch S6, the layer pusher bar 56is cause to move from the left side to the right side of the unstackingplatform. The empty pallet 24 on this platform being in the path of thepusher bar is thereby moved to the pallet stacker elevator as indicatedin FIGS. 3 and 4. To thus actuate the pusher bar, solenoid 64 isenergized through a circuit shown in FIG. 13. It includes contacts C18of relay R4, contacts C19 of relay R3, contacts C20 of relay R11,contacts C21 of relay R8, contacts C2 of relay R6 and the coil ofsolenoid 64. Valve 62 is thereby operated to cause the pusher to move tothe right. Operation of valve 62 requires only momentary energization ofits actuating solenoids 63 or 64.

Just prior to the arrival of the pusher at its extreme right positionlimit switch S is actuated to close a circuit at its contact S10b andopen another circuit at its contact 810a. As indicated in FIG. 12, theopening of the circuit at 810a causes relay R11 to drop out and theclosing at contact 81% completes a circuit which includes contacts C4 ofrelay R5, contacts C23 of relay R6, contact 81% of switch S10 and thecoil of relay R2. Relay R2 is thereupon held in through its contacts C8,the holding circuit including contacts C4, 57a of switch S7 and contactsC8 and the coil of relay R2. Solenoid 77 is now energized through thecircuit which includes contacts C4 of R5 and C9 of R2.

In the meantime the pusher finishes its stroke to the right and comes torest, closing switch S13. The hoist then moves down to its bottomposition where it closes switch S8 to complete a circuit including thecoil of relay R5. Contacts C4 of relay R5 open to cause relay R2 to dropout, open the circuit including solenoid 77 and stop the downward travelof the hoist.

Normally open contacts C24 of relay R5 now close to energize solenoid 83and cause clamping jaw 30 to move out to its open position indicated inbroken lines in FIG. 3. When this jaw reaches its wide open positionrelay R3 is energized due to the closing of switch S3. Relay R8 is nowenergized by current fed through contacts C13 of relay R2, contacts C25of relay R5, and contacts C26 of relay R3. Upon the closing of itscontacts C15, relay R8 is locked in while the hoist moves up. Upwardmovement is started when solenoid 78 is energized, current being fedthrough contacts C13 of relay R2, contact C16 of relay R6, contacts C17of relay R8 and solenoid 78 Upward movement of the hoist continues untilswitch S6 is gain closed to energize relay R6 and open the circuitincluding solenoid 78, thereby stopping upward movement of the hoist. Atthe same time clamping jaw 30 is activated to move in to its grippingposition. This clamp circuit includes contacts C27 of relay R11,contacts C28 of relay R6, contacts C11 of relay R7, C12 of R3 andsolenoid 82 actuating valve 81.

Assum'mg that there are a plurality of layers of cartons resting on theplatform 25, clamp jaw 30 will again be closed to grip all layers exceptthe bottom layer, be ing activated by solenoid 82. Pin actuates switchS2 to close at its contacts 8% which is in series with switch S11 andthe coil of relay R9. Fluid pressure in the device 86 now increasesuntil switch 11 is closed, causing relay R9 and solenoid 78 to beenergized. The hoist carrying its load of cartons now moves up, thepertinent circuit including contacts C13 of relay R2, contacts C29 ofrelay R9, contacts C30 of relay R6, contacts C31 of relay R11, contactsC17 of relay R8 and solenoid 78.

Upward movement of the hoist is stopped mechanically leaving solenoid 78energized when the hoist reaches its top position where it closes switchS5. As indicated in FIG. 13, closing this switch feeds current toenergize relay R7, and activate pusher bar 56 to push a layer of cartonsoff of platform to platform 36. The pusher bar is thus moved byenergizing solenoid 63 which is included in a circuit including contactsC32 of relay R11, contacts C33 of relay R7 and switch S13 and switchS14. The free layer of cartons on the unstacking platform 25 is therebypushed to the extreme left position of the pusher bar 56 where it closesswitch 12. Solenoid 63 is now deenergized due to the opening of switchS13. It will be evident that solenoid 63 cannot be energized as long asthere is a carton on platform 36 in position to hold switch S14 open.

Upon the arrival of a layer of cartons on live rollers 37 of platform 36these rollers convey the cartons to the discharge conveyor 39, one rowat a time Switches S4 and S441 are actuated to open the circuit forenergizing motor 38, thereby stopping the rollers 37 momentarily as eachrow is delivered to conveyor 39. As hereinbefore described, the rollersof the conveyor are so operated as to accelerate and space the cartonsas each of them arrives on or adjacent to the turning device comprisingthe belt 42. Thus the cartons are discharged along the conveyor 39 inspaced end to end relative positions irrespective of their relativeposition when they are received on this conveyor. When each row clearsthe switches 4 and S451, another row is fed to the discharge conveyor byoperation of the rollers 37 until all cartons of the layer have beendischarged from the machine. 7

During the discharge of one layer of cartons from platform 36 anotherlayer is deposited on the platform 25 by a repetition of the operationsof the hoist and clamp mechanism and solenoid 64 for activating thepusher bar to its position at the right side of the platform. Asindicated in EEG. 13, this pusher circuit includes contacts C13 of relayR4, contacts C34 of relay R7, contacts C35 of relay R9 and solenoid 64.The hoist with its load starts down again when the pusher mechanismcloses switch S10 at its contact S1012 thereby closing the circuitincluding contacts C4 of relay R5, contacts C23 of relay R6, contactsS1011 of switch S10 and the coil of relay R2. Again this relay is lockedin through its contacts C3. The holding circuit for relay R2 nowincludes contact C4 of relay R5, contacts C36 of relay R11 and contactsC8 of relay R2. Switch S8 is actuated by the hoist when it reaches itsbottom position to open the circuit at contacts C4 of relay R5 feedingrelay R2. This relay and solenoid 77 are thereby deenergized and thehoist stops in a position to deposit another layer of cartons on theplatform 25. This layer is released from the clamping jaws when contactsS24 of relay R5 feed current to solenoid 83 causing the clamp jaw 30 tomove out.

Upward movement to a position determined by the elevation of switch S6follows when switch S3 is closed to energize relay R3. Contacts C26 ofrelay R3 then close a circuit including contacts S13 of relay R2, C25 ofR5 C26 of R3 and the coil of relay R8. Contacts C17 of relay R8 thenclose a circuit including solenoid 73 causing the hoist to move up.Relay R8 is held in through its contacts C15, and the circuit includingcontacts C13 of R2 and solenoid 78 is energized through the branchcircuit including contact C16 of relay R6 and contacts C17 of relay R8.

The closing of switch S6 energizes relay R6 to stop upward movement ofthe hoist and to cause clamp jaw 30 to move in to grip the layer orlayers resting on the bottom layer. As hereinbefore pointed out, thisclamping circuit includes contacts C27 of relay R11, C28 of R6, C11 ofR7 and C13 of R3 and solenoid 82. With one or more layers of cartons inthe grip of the jaws 30, 30a, the hoist now moves up to its topposition. Relay R9 being energized by the closing of switch S11 andcontact S211, solenoid 78 is energized again through the circuitincluding contact C13 of relay R2, C29 of R9, C30 of R6, C31 of R11 andC17 of R8 to cause the hoist to move up. This frees the layer remainingon the platform 25 so that this layer is discharged as in the case ofthe first layer. Upon reaching its top position the hoist is stoppedmechanically, closes switch S5 and switch S6 remains closed.

The hoist carrying its load of cartons from its top position moves downwhen solenoid 77 and relay R2 are energized. This relay is energizedupon the closing of contact S1012 of switch S10, the circuit includingnormally closed contact C4 of relay R5 and contacts C26 of relay R6.Solenoid 77 is now energized by current fed through contact C4 of relayR5 and contact C9 of relay R2. There upon the operation of the hoist,clamp and pusher bar is repeated, as described, until the last layer ofthe stack has been deposited and the hoist goes up to its position whereit closes switch S6. Assuming that there are no cartons between the jawswhen they are closed, switch S2 remains closed at its contact 82a andpressure actuated switch S11 is closed by fluid pressure in conduit 85and device 86 which builds up when the piston in cylinder 79 reaches theend of its stroke to the left. Relay R is thereby energized to by-passthe contacts of relay R9. The circuit for energizing relay R10 includescontacts 27 of relay R11, C28 of R6, switch S11 and switch S2, contact82a. Relay R8 remains energized by current fed through contacts C13 ofR2, and holding contacts C15. Solenoid 73 is now energized by currentfed through contacts C13 of R2, C of R8, C37 of R10, C30 of R6, 031 ofR11 and C17 of R8, causing the hoist to move up to switch S5. Thisswitch now closes the circuit including contacts C39 of relay R10 andsolenoid 83, causing the jaw 30 to move out to close switch S3,activating relay R3.

Pusher bar 56 having removed the last layer of cartons from platform 25,stops in position to close switch S12 and the circuit energizing relayR4. Relays R4, R3 and R7 are now energized to complete a circuitincluding contacts C40 of relay R4, C31 of R3, C32 of R7, C42 of R11 andthe coil of relay R11. This completes a cycle and resets the severalcircuits to repeat the cycle when stack of cartons is delivered to feedconveyor in position to close switch S9.

Summary of Hoist and Clamp Cycle (1) Starting with the hoist in its topposition where it closes switch S5 and with the clamp jaws open, thehoist moves down to switch S7 where the clamps close on all cartonsabove the pallet.

(2) With a complete stack of cartons in the grip of the jaws, the hoistmoves up to switch S6 at which time the pusher bar 56 is actuated totransfer the empty pallet from platform to pallet elevator 55.

(3) The hoist moves down to its bottom position, closing switch S8,where the clamp jaws open to deposit the load of cartons on platform 25.

(4) With the clamp jaws open the hoist moves up to switch S6 where thejaws close on all layers of cartons above the bottom layer.

(5) The hoist lifts its load to the top position, closing switch S5.This activates the pusher bar to transfer the bottom layer of cartonsfrom platform 25 to platform 36.

(6) Then, moving down to its bottom position, the hoist deposits itsremaining load on platform 25 and the clamp jaws open.

Operations (4), (5) and (6) are thereupon repeated until the last layerhas been deposited on platform 25 and the hoist moves up to switch S6with the clamp jaws open.

(7) The clamp jaws close at the elevation of switch S6, but with nolayer between the jaws, switch S2 remains open at its contact S212 andclosed at S2a. This causes the hoist to move up to switch S5, where itstops and the jaws open ready to start a new cycle when another stack isfed to conveyor 20 in position to close switch S9.

Modification for Operation Without Pallets To adapt my machine toreceive stacks which are not supported on pallets only two simplemodifications are required. For such operation the pallet stackingelevator 55 may be eliminated and limit switch S7 is merely moved downto a position which insures a firm grip on all layers of a stack but atan elevation slightly above the bottom position of the hoist whereswitch S8 is closed. Thus, during each cycle of operation the first timethe hoist starts down from its top position with the clamp jaws open itwill stop at the elevation of switch S7, slightly above switch S8. Atthis elevation the clamping jaws and hoist 10' pick up all layers, moveup to switch S6 and stop as described. The pusher bar or ram moves toits right position where it stops also as described. No other modi-ification is required in the activating means for completing theautomatic operation through the cycle hereinbefore described in detail.

Other modifications of the invention may be made within the scope of theappended claims.

The present application is a division of my application Serial No.686,431, filed September 26, 1957, for Carton Unstacking Machine.

I claim:

1. A carton nus-tacking machine adapted to receive a succession ofstacks of cartons, each stack containing a plurality of layers composedof one or more rows of cartons, comprising: a first platform defining anunstacking area, a second platform defining a layer receiving area atone side of said first platform; a hoist associated with said firstplatform including a supporting frame, a vertically reciprocablecarriage mounted on said frame, first power actuated means for raisingand lowering said carriage on said frame, a pair of clamping jawspositioned on said carriage to engage opposite sides of layers ofcartons on said first platform, second power actuated mean-s for movingsaid clamping jaws into and out of engagement with the carton layers;control means for sequentially energizing said second power actuatedmeans to cause said clamping jaws to clamp carton layers composed of aplurality of cartons above a bottom layer, then energizing said firstpower means to lift said layers to a predetermined elevation andthereafter lower said layers to said first platform, and layer movingmeans disposed to transfer cartons from said first platform to saidsecond platform when the cartons of the upper layer or layers of eachstack are in said predetermined elevated position on said hoist, wherebythe successive bottom layers of articles are transferred laterally fromsaid first platform to said second platform.

2. A machine in accordance with claim 1 wherein said first poweractuated means and second power actuated means each comprise fluidpressure responsive means, and valves severally controlling theoperation of said fiuid pressure responsive means; and said controlmeans including electro-magnetic means for actuating the several valves,limit switches disposed to be actuated by said cmriage and clamping jawswhen in pro-determined positions and electric circuit means forenergizing the electro-magnetic means under control of said limitswitches.

3. A machine in accordance with claim 1 in which said layer moving meanscomprises a bar projecting above the upper surface of said firstplatform and disposed to slide the layers successively to said secondplatform and means for imparting reciprocating movement to said bar fromone side of said first platform to the other side of said platform.

4. A carton unstacking machine in accordance with claim 1, in which saidcontrol means includes interlocking electric circuits, electro magneticmeans in said circuits for activating said first and second power means,and limit switches included in said circuits and disposed to be actuatedby said carriage, clamping jaws and layer moving means respectively atpredetermined positions of the same.

5. A machine in accordance with claim 4 in which said control meansinclude electrical activating means for said layer moving means,interlocking circuits and limit switches for activating said layermoving means in timed relation to the operation of said carriage andstack clampingjaws.

6. A machine in accordance with claim. 4 in which said control meansinclude, a first normally open switch disposed to be closed when thecarriage is in a top position, an electric circuit including means undercontrol of said first switch for energizing said layer moving means, asecond normally open switch disposed tobe closed when the carriage is ina stack gripping position at an intermediate elevation above the bottomlayer of cartons resting on said first platform, an electric circuitincluding means under control of said second switch for stoppingdownward movement of the carriage at said intermediate elevation, athird normally open switch disposed to be closed when the carriage is ina bottom position wherein the bottom layer of cartons resting on saidfirst platform may be released by said clamping jaws, and a circuitincluding means under control of said third switch for stopping downwardmovement of the carriage when in said bottom position.

7. A machine in accordance with claim 6 in which said control meansinclude means for activating said second power actuated means to movesaid clamping jaws to open position under control of said third switch,a fourth normally open switch disposed to be closed when said clampingjaws are in open position, and a circuit including means for activatingsaid clamping jaws to closed position when said second and fourthswitches are closed.

8. A machine in accordance with claim 6 in which at least one of saidstack clamping jaws is movable between an open position and a closedgripping position, and said control means include, a fourth normallyopen switch disposed to be closed when the jaw is in open position, acircuit including means adapted to be energized when said second andfourth switches are closed for activating said second power actuatedmeans to move said jaw to closed position, a circuit including meansenergized when said third switch is closed for activating said secondpower actuated means to move said jaw to open position, a fifth normallyopen switch disposed to be closed when said jaw is in carton grippingposition, a sixth normally open switch disposed to be closed by saidlayer moving means when in a predetermined position, a circuit includingmeans energized when said fifth and sixth switches are closed foractivating said first power actuated means to move said carriagedownwardly, and a circuit including means energized when said second andfifth switches are I closed for activating said first power actuatedmeans to move said carriage upwardly.

9. In a carton unstacking machine adapted to receive a succession ofstacks of cartons, each stack containing a plurality of layers composedof one or more rows of cartons, a platform defining an unstacking area,a hoist associated with said platform, and including a verticallymovable clamp mounting carriage, power actuated means for raising andlowering said carriage, a pair of substantially parallel, horizontallyspaced clamping jaws attached to said carriage and having verticallydisposed gripping surfaces adapted to frictionally engage opposite sidesrespectively of a plurality of carton layers each composed of aplurality of cartons, power actuated means for moving at least one ofsaid clamping jaws toward and away from the other clamping jaw, controlmeans for sequentially actuating both of said power actuated means tocause said clamping jaws to clamp layers of cartons above a bottom layeron said platform, lift said layers above said bottom layer by actuatingsaid power means to lift said carriage and thereafter lower said layersto said first platform, release said layers and repeat the cycle asrequired, and power actuated means for remov-t ing the bottom cantonlayer from said platform in timed relation to the lifting of the layersabove.

References Cited in the file of this patent UNITED STATES PATENTS548,056 Hewitt Oct. 15, 1895 1,330,639 Leumann Feb. 10, 1920 2,211,511Melzer et a1 Aug. 13, 1940 2,536,151 Backofen Jan. 2, 1951 2,599,262Kvederis June 3, 1952 2,701,650 Stevenson Feb. 8, 1955 2,702,132 V-anDoran Feb. 15, 1955 2,702,646 Van Doran Feb. 22, 1955 2,731,131 ShannonJan. 17, 1956 2,769,570 Adams Nov. 6, 1956 2,885,111 Vann et al May 5,1959 2,890,807 Parcell June 16, 1959

1. A CARTON UNSTACKING MACHINE ADAPTED TO RECEIVE A SUCCESSION OF STACKSOF CARTONS, EACH STACK CONTAINING A PLURALITY OF LAYERS COMPOSED OF ONEOR MORE ROWS OF CARTONS, COMPRISING: A FIRST PLATFORM DEFINING ANUNSTACKING AREA, A SECOND PLATFORM DEFINING A LAYER RECEIVING AREA ATONE SIDE OF SAID FIRST PLATFORM; A HOIST ASSOCIATED WITH SAID FIRSTPLATFORM INCLUDING A SUPPORTING FRAME, A VERTICALLY RECIPROCABLECARRIAGE MOUNTED ON SAID FRAME, FIRST POWER ACTUATED MEANS FOR RAISINGAND LOWERING SAID CARRIAGE ON SAID FRAME, A PAIR OF CLAMPING JAWSPOSITIONED ON SAID CARRIAGE TO ENGAGE OPPOSITE SIDES OF LAYERS OFCARTONS ON SAID FIRST PLATFORM, SECOND POWER ACTUATED MEANS FOR MOVINGSAID CLAMPING JAWS INTO AND OUT OF ENGAGEMENT WITH THE CARTON LAYERS;CONTROL MEANS FOR SEQUENTIALLY ENERGIZING SAID SECOND POWER ACTUATEDMEANS TO CAUSE SAID CLAMPING JAWS TO CLAMP CARTON LAYERS COMPOSED OF APLURALITY OF CARTONS ABOVE A BOTTOM LAYER, THEN ENERGIZING SAID FIRSTPOWER MEANS TO LIFT SAID LAYERS TO A PREDETERMINED ELEVATION ANDTHEREAFTER LOWER SAID LAYERS TO SAID FIRST PLATFORM, AND LAYER MOVINGMEANS DISPOSED TO TRANSFER CARTONS FROM SAID FIRST PLATFORM TO SAIDSECOND PLATFORM WHEN THE CARTONS OF THE UPPER LAYER OR LAYERS OF EACHSTACK ARE IN SAID PREDETERMINED ELEVATED POSITION ON SAID HOIST, WHEREBYTHE SUCCESSIVE BOTTOM LAYERS OF ARTICLES ARE TRANSFERRED LATERALLY FROMSAID FIRST PLATFORM TO SAID SECOND PLATFORM.